package org.bouncycastle.crypto.engines;import org.bouncycastle.crypto.CipherParameters;import org.bouncycastle.crypto.DataLengthException;import org.bouncycastle.crypto.params.KeyParameter;/** * a class that provides a basic DESede (or Triple DES) engine. */public class DESedeEngine    extends DESEngine{    protected static final int  BLOCK_SIZE = 8;    private int[]               workingKey1 = null;    private int[]               workingKey2 = null;    private int[]               workingKey3 = null;    private boolean             forEncryption;    /**     * standard constructor.     */    public DESedeEngine()    {    }    /**     * initialise a DESede cipher.     *     * @param encrypting whether or not we are for encryption.     * @param params the parameters required to set up the cipher.     * @exception IllegalArgumentException if the params argument is     * inappropriate.     */    public void init(        boolean           encrypting,        CipherParameters  params)    {        if (!(params instanceof KeyParameter))        {            throw new IllegalArgumentException("invalid parameter passed to DESede init - " + params.getClass().getName());        }        byte[]      keyMaster = ((KeyParameter)params).getKey();        byte[]      key1 = new byte[8], key2 = new byte[8], key3 = new byte[8];        if (keyMaster.length > 24)        {            throw new IllegalArgumentException("key size greater than 24 bytes");        }                this.forEncryption = encrypting;        if (keyMaster.length == 24)        {            System.arraycopy(keyMaster, 0, key1, 0, key1.length);            System.arraycopy(keyMaster, 8, key2, 0, key2.length);            System.arraycopy(keyMaster, 16, key3, 0, key3.length);            workingKey1 = generateWorkingKey(encrypting, key1);            workingKey2 = generateWorkingKey(!encrypting, key2);            workingKey3 = generateWorkingKey(encrypting, key3);        }        else    // 16 byte key        {            System.arraycopy(keyMaster, 0, key1, 0, key1.length);            System.arraycopy(keyMaster, 8, key2, 0, key2.length);            workingKey1 = generateWorkingKey(encrypting, key1);            workingKey2 = generateWorkingKey(!encrypting, key2);            workingKey3 = workingKey1;        }    }    public String getAlgorithmName()    {        return "DESede";    }    public int getBlockSize()    {        return BLOCK_SIZE;    }    public int processBlock(        byte[] in,        int inOff,        byte[] out,        int outOff)    {        if (workingKey1 == null)        {            throw new IllegalStateException("DESede engine not initialised");        }        if ((inOff + BLOCK_SIZE) > in.length)        {            throw new DataLengthException("input buffer too short");        }        if ((outOff + BLOCK_SIZE) > out.length)        {            throw new DataLengthException("output buffer too short");        }        if (forEncryption)        {            desFunc(workingKey1, in, inOff, out, outOff);            desFunc(workingKey2, out, outOff, out, outOff);            desFunc(workingKey3, out, outOff, out, outOff);        }        else        {            desFunc(workingKey3, in, inOff, out, outOff);            desFunc(workingKey2, out, outOff, out, outOff);            desFunc(workingKey1, out, outOff, out, outOff);        }        return BLOCK_SIZE;    }    public void reset()    {    }}